“Ducking” is a term used in audio track mixing in which a background track (e.g., a music track), is attenuated when another track, such as a voice track, is active. Ducking allows the voice track to dominate the background music and thereby remain intelligible over the music. In another typical ducking implementation, audio content featuring a foreign language (e.g., in a news program) may be ducked while the audio of a translation is played simultaneously over the top of it. In these situations, the ducking is performed manually, typically as a post-processing step.
Some applications of audio ducking also exist that may be implemented in realtime. For example, an emergency broadcast system may duck all audio content that is being played back over a given system, such as broadcast television or radio, in order for the emergency broadcast to be more clearly heard. As another example, the audio playback system(s) in a vehicle, such as an airplane, may be configured to automatically duck the playback of audio content in certain situations. For instance, when the pilot activates an intercom switch to communicate with the passengers on the airplane, all audio being played back via the airplane's audio systems may be ducked so that the captain's message may be heard.
In some audio output devices, such as smartphones and tablets, audio ducking may be initiated when notifications or other communications are delivered by the device. For instance, a smartphone that is playing back audio content via an audio source may duck the audio content playback when a phone call is incoming. This may allow the user to perceive the phone call without missing it.
Audio output devices may provide a user with audio signals via speakers and/or headphones. The audio signals may be provided so that they seem to originate from various source locations inside or around the user. For example, some audio output devices may move an apparent source location of audio signals around a user (front, back, left, right, above, below, etc.) as well as moved closer to and farther from the user.